The critical steps for recovering an autonomous underwater vehicle are the step of creating a connection between the ship and the underwater vehicle and the step of loading the underwater vehicle on board the ship.
Solutions are known in which a physical connection is established between the underwater vehicle and the ship by means of a flexible connection which is attached to the top of the underwater vehicle. Once this connection has been established, the underwater vehicle is lifted by means of a crane or a gantry, then the underwater vehicle is placed on board the ship. However, cranes and gantries are heavy and bulky equipment and it is desirable to avoid installing such equipment on board small ships. Moreover, during the phase of loading on board in rough seas, the underwater vehicle which is suspended on the crane or gantry is subjected to considerable movement which may cause it to strike the ship or the equipment thereof and to damage said equipment or to be damaged itself.
Solutions are known which permit these drawbacks to be remedied in which a physical connection is established between the underwater vehicle and the ship by means of a flexible connection which is attached to the front of the AUV. Once this connection has been established, the cable is wound up in order to lift the underwater vehicle on board the ship, for example, by sliding it on an inclined plane. The phase of launching the underwater vehicle into the sea is carried out by unwinding the cable.
One solution of this type comprises a receiving device which comprises receiving means having a flared shape which are capable of receiving the front part of the underwater vehicle. This receiving device comprises blocking means which permit the front part of the vehicle to be blocked in the receiving means and is connected to the ship by means of a cable fixed to the receiving means on the front of the ship so as to be able to pull the underwater vehicle from the ship by means of the cable and to lift the underwater vehicle onto the boat via an inclined plane.
Once the connection has been established with the receiving device and it has been towed by the ship, this solution has the drawback of not permitting the AUV to continue its mission of recording images of the sea bed by means of an active sonar device which is installed on board, the AUV tending to rise to the surface under the action of the force exerted by the cable which is subjected to a hydrodynamic drag force when the ship moves forward. This solution is not optimal since the AUV has limited endurance which does not permit it to carry out a mission of long duration.